EP0517545A2 - Appareil d'enregistrement et procédé pour la génération de données d'actionnement - Google Patents

Appareil d'enregistrement et procédé pour la génération de données d'actionnement Download PDF

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Publication number
EP0517545A2
EP0517545A2 EP92305187A EP92305187A EP0517545A2 EP 0517545 A2 EP0517545 A2 EP 0517545A2 EP 92305187 A EP92305187 A EP 92305187A EP 92305187 A EP92305187 A EP 92305187A EP 0517545 A2 EP0517545 A2 EP 0517545A2
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European Patent Office
Prior art keywords
pixel
recording
processing
dots
halftoning processing
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Granted
Application number
EP92305187A
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German (de)
English (en)
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EP0517545A3 (en
EP0517545B1 (fr
Inventor
Hideki c/o Canon Kabushiki Kaisha Tanaka
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Canon Inc
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Canon Inc
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Publication of EP0517545A3 publication Critical patent/EP0517545A3/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/12—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanning
    • H04N1/126—Arrangements for the main scanning
    • H04N1/128—Arrangements for the main scanning using a scanning head arranged for linear reciprocating motion
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K15/00—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers
    • G06K15/02—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers
    • G06K15/10—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by matrix printers
    • G06K15/102—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by matrix printers using ink jet print heads
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/032—Details of scanning heads ; Means for illuminating the original for picture information reproduction
    • H04N1/034—Details of scanning heads ; Means for illuminating the original for picture information reproduction using ink, e.g. ink-jet heads
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
    • H04N1/1911—Simultaneously or substantially simultaneously scanning picture elements on more than one main scanning line, e.g. scanning in swaths
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
    • H04N1/1911—Simultaneously or substantially simultaneously scanning picture elements on more than one main scanning line, e.g. scanning in swaths
    • H04N1/1913—Scanning adjacent picture elements in different scans of the array, e.g. in complementary checkerboard patterns
    • H04N1/1915—Scanning adjacent picture elements in different scans of the array, e.g. in complementary checkerboard patterns with subscan displacement of the array between successive scans
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/40025—Circuits exciting or modulating particular heads for reproducing continuous tone value scales
    • H04N1/40031—Circuits exciting or modulating particular heads for reproducing continuous tone value scales for a plurality of reproducing elements simultaneously
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/405—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
    • H04N1/4051—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a dispersed dots halftone pattern, the dots having substantially the same size
    • H04N1/4052—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a dispersed dots halftone pattern, the dots having substantially the same size by error diffusion, i.e. transferring the binarising error to neighbouring dot decisions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/405—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
    • H04N1/4055—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a clustered dots or a size modulated halftone pattern
    • H04N1/4057—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a clustered dots or a size modulated halftone pattern the pattern being a mixture of differently sized sub-patterns, e.g. spots having only a few different diameters
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K2215/00—Arrangements for producing a permanent visual presentation of the output data
    • G06K2215/111—Arrangements for producing a permanent visual presentation of the output data with overlapping swaths

Definitions

  • the present invention relates to a recording apparatus and a method of forming driving data for recording elements used in recording thereof, which are used in word processors, copy machines, facsimiles and so on, and used in a printer connected to a host computer for outputting information from host computer, and more particularly to a recording apparatus and a method of forming driving data used therefor using a serial type of recording head.
  • Characters and visualized images recorded on recording media such as recording sheets are digitized images generally formed by a set of pixels, each of which has individual density level (gray level) data. Each pixel is composed of a dot formed on the recording media by the recording head.
  • recording heads for forming dots a thermal transfer method and an ink jet recording method are widely known. Among them, an ink jet recording method has been widely used in recent years and it has many advantages in enabling relatively high fine-pitched dot formation and high speed recording.
  • a dot density is assigned to each pixel according to these density level data, and the dot pattern for each pixel is determined in accordance with the dot density.
  • Definition forms of the dot patterns are categorized into two groups, one refers to a method that a plurality of dots are placed in an identical position in responsive to the dot density, and the other refers to a method that a designated dot pattern is developed with a plurality of dots in responsive to the dot density.
  • the dot pattern of each pixel has any patterns, it is necessary to determine driving data for driving recording elements of the recording head so as to form those dot patterns.
  • the driving data can be obtained as described hereinafter.
  • ⁇ Gamma
  • color correction color correction
  • undercoat eliminating processing as well as a multi-level halftoning (gray scale) processing (pseudo-halftoning process) corresponding to the number of dots which form each pixel.
  • a multi-level halftoning (gray scale) processing prseudo-halftoning process
  • error diffusion method a dither method, etc are known in the art.
  • reference numeral 1001 denotes a specified pixel in which the multi-level halftoning processing is to be performed, and it has data I(x,y).
  • I(x,y) is the product of original 8-bit density level data (representing levels between 0 to 255) of the specified pixel (x,y) and an error produced by the multi-level halftoning processing in the pixel in which the multi-level halftoning processing has been already performed.
  • Numerals 1002 to 1008 denote pixels in which the multi-level halftoning processings have already been performed, and these pixels are surrounding pixels of the specified pixel.
  • Each of constants a to g inside these pixels represents a multi-level value which is obtained by performing the multi-level halftoning processing.
  • the five-level values a to g are integers among 0 to 4.
  • Fig. 2 represents constants A to G for weighting the respective pixels in each of which the five-level halftoning processing has been performed. These constants are used to determine a threshold level for the five-level halftoning processing.
  • the ERROR is distributed at a certain predetermined rate to several pixels which are the surrounding pixels and in each of which the five-level halftoning processing has not yet been performed.
  • the five-level value of each pixel can be obtained by carrying out in order the processing described hereinabove on each pixel, wherein the five-level value corresponds to the number of dots of each pixel as mentioned above.
  • CMOS complementary metal-oxide-semiconductor
  • CMOS complementary metal-oxide-semiconductor
  • a multiple-droplet system in which a single dot is formed in appearance by causing a plurality of ink-droplets to be projected substantially on an identical position of the recording media.
  • both of them are constructed such that a plurality of dots of one pixel are formed by a single recording element.
  • the plurality of dots are formed by each of ink-droplets ejected from one ink orifice (ink jet nozzle).
  • ink jet nozzle ink jet nozzle
  • the densities of pixels become different from each other.
  • the deterioration in quality of picture arises in the cause of multitude of different shades (lighter and darker variations) appeared in a recorded image.
  • an improved system was proposed by the assignee of the present invention.
  • one pixel is composed of a plurality of dots and each of these dots are formed by the respective different recording element.
  • the improved system and the conventional pseudo-halftoning processing are combined with each other, it is further necessary to assign each of recording elements to the multi-level value data of each pixel obtained by the pseudo-halftoning processing.
  • the inventors of the present invention directed their attention to the fact that the data which are assigned to recording elements and are called the driving data are binary data having value "0" or "1", and thought out that the processing for generating the driving data and assigning them to the recording elements was performed simultaneously with the comparing processing with the threshold level in the pseudo-halftoning processing.
  • An object of the present invention is, therefore, to provide more improved method of forming driving data.
  • the number of processing steps in the pseudo-halftoning processing and that in a processing for assigning driving data to each recording element on the basis of the pseudo-halftoning processing can be decreased, as a result, the loads on hardware and/or software can be reduced.
  • the two-level halftoning processing may be performed in corresponding with each of (n-1) recording elements used for forming the dots composing the pixels.
  • the two-level halftoning processing may be performed in correspondence with each of (n-1) dots composing the pixels.
  • the two-level halftoning processing may be performed in correspondence with each of pseudo-pixels made by dividing the pixel into (n-1) pixels.
  • An error produced by the two-level halftoning processing may be distributed to other pseudo-pixels.
  • the pixel may be composed of the plurality of dots, and each of the plurality of dots may be formed by different recording element during respective scanning of the recording head.
  • the recording element of the recording head may include an orifice for ejecting ink, and means for generating heat energy utilized for ejection of ink from the orifice, whereby a bubble is generated by the heat energy, the ink is ejected from the orifice according to the generation of the bubble, and the dots are formed by the ejected ink.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be sequentially selected.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected at random.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected according to a position of the pixel on the image.
  • the pixel may be composed of the plurality of dots, and each of the plurality of dots may be formed by different recording element during respective scanning of the recording head.
  • the recording elements of the recording head may include an orifice for ejecting ink, and means for generating heat energy utilized for ejection of ink from the orifice, whereby a bubble is generated by the heat energy, the ink is ejected from the orifice according to the generation of the bubble, and the dots are formed by the ejected ink.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be sequentially selected.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected at random.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected according to a position of the pixel on the image.
  • a method of forming driving data for a recording apparatus which uses a recording head having a plurality of recording elements and in which the recording elements is driven according to the driving data to form dots to a recording medium so that an image is recorded with a set of pixels composed of the dots
  • the two-level halftoning processing may be performed in corresponding with each of (n-1) recording elements used for forming the dots composing the pixels.
  • the two-level halftoning processing may be performed in correspondence with each of (n-1) dots composing the pixels.
  • the two-level halftoning processing may be performed in correspondence with each of pseudo-pixels made by dividing the pixel into (n-1) pixels.
  • An error produced by the two-level halftoning processing may be distributed to other pseudo-pixels.
  • the pixel may be composed of the plurality of dots, and each of the plurality of dots may be formed by different recording element during respective scanning of the recording head.
  • the recording element of the recording head may include an orifice for ejecting ink, and means for generating heat energy utilized for ejection of ink from the orifice, whereby a bubble is generated by the heat energy, the ink is ejected from the orifice according to the generation of the bubble, and the dots are formed by the ejected ink.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be sequentially selected.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected at random.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected according to a position of the pixel.
  • the pixel may be composed of the plurality of dots, and each of the plurality of dots may be formed by different recording element during respective scanning of the recording head.
  • the recording element of the recording head may include an orifice for ejecting ink, and means for generating heat energy utilized for ejection of ink from the orifice, whereby a bubble is generated by the heat energy, the ink is ejected from the orifice according to the generation of the bubble, and the dots are formed by the ejected ink.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be sequentially selected.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected at random.
  • the recording elements to which the result of the two-level halftoning processing is assigned may be selected according to a position of the pixel on the image.
  • Fig. 3 is a perspective view showing major parts of an ink jet recording apparatus of one embodiment of the present invention.
  • the recording head for example, 32 orifices with their mutual interval being 63.5 ⁇ m (400 dots per inch) are placed in an array extended in the direction in which the recording paper 2 is fed, this direction designated sub-scanning direction, and in each ink path connecting to each corresponding orifice, installed is a heater for generating thermal energy used for ejecting ink droplets.
  • the heater generates thermal energy in responsive to electric pulses correlated with driving signal data, and film boiling occurs in the ink fluids which leads to generating a bubble and finally to ejection of an ink droplets from the orifice.
  • the frequency of heater driving signals that is, the ejection frequency
  • the ejection frequency is 2 kHz.
  • term “discharging portion”, “outlet” or “nozzle” may be used instead of term “orifice”.
  • a carriage 4 on which a recording head 1 is mounted is supported by a couple of guide shafts 5A and 5B so as to move freely along the guide shafts 5A and 5B.
  • this movement of the recording head 1 is called main-scanning and its scanning direction is called main-scanning direction.
  • the carriage 4 is fixed on a part of a belt expanded by pulleys and the carriage 4 is moved by rotational movements of pulleys driven by the motor linked with the pulleys. In Fig. 3, these pulleys and the motor are not shown.
  • An ink tube 6 is connected to the recording head 1, through which the ink fluids can be supplied from an ink tank not shown to the recording head 1.
  • a flexible cable 7 is connected to the recording head 1 which can transmit driving signals corresponding to recording data and control signals from a host apparatus or a control part of the ink jet recording apparatus to a head driving circuit (a head driver).
  • the ink supply tube 6 and the flexible cable 7 are composed of flexible materials so as to follow the movement of the carriage 4.
  • the longer side of the platen roller 3 is extended in parallel to the guide shafts 5A and 5B and the platen roller 3 is driven by a paper feed motor not shown and used for feeding a recording sheet 2 as recording media and for defining a recording face of the recording sheet 2.
  • the recording head 1 ejects the ink fluids on the recording face of the recording sheet 2 in front of the orifices of the recording head 1.
  • Fig. 4 is a block diagram showing a control structure of the ink jet recording apparatus as shown in Fig. 3.
  • a main controller 1100 is composed of CPU and so on, and transfers image data supplied from a host computer 200 into density level data of each pixel and store the density level data into the frame memory 1100M.
  • the main controller 1100 supplies the density level data of each pixel stored in the frame memory 1100M to the driver controller 1110 in predetermined timing.
  • the driver controller 1110 converts the density level data supplied from the frame memory 1100M into drive data which describes turn-on or turn-off signals to each heater of the recording head 1 and each of which corresponds to a respective orifice index number and respective scan number.
  • the orifice index number is the order of the orifice array in the recording head and the scan number is the sequential number of iterative main-scanning operations.
  • the drive data converted by the driver controller 1110 are stored in the drive data RAM 1110M.
  • the driver controller 1110 read out the drive data stored in the drive data RAM 1110M by referring their orifice index number and scan number in responsive to control signals from the main controller 1100, and supplies the read-out drive data into the head driver 1110D and controls its driving timing.
  • the main controller 1100 controls the ink ejection by the recording head 1 and the rotational movements of the carriage drive motor 1104 and the paper feed motor 1102 through the driver controller 1110, the motor driver 1104D and the motor driver 1102D. So far, characters and graphic images corresponding to input image data are recorded on the recording sheet 2.
  • the driver controller 1110 converts the density level data into the drive data
  • this conversion may be performed by the main controller 1100.
  • the drive data can be stored in the frame memory 1100M and hence, the RAM 1110M can be removed.
  • Fig. 5 is a schematic illustration of forming one pixel by using ink droplets ejected from a plurality of ink orifices.
  • the recording head 601 has a plurality of orifices, for example, 128 orifices.
  • the recording head 601 is moved from left to right in Fig. 5.
  • the dots of each pixel are formed by the ink droplets ejected from each orifice in accordance with the assigned driving data.
  • a reference numeral 601A denotes the position of initial scanning of the recording head 601 with respect to a recording medium
  • numerals 601B, 601C, 601D each denotes a subsequent position of scanning in order.
  • a numeral 602 denotes one pixel recorded by the above scanning.
  • the numbers prefixed by a symbol # denote orifice numbers of each orifice in the recording head 601.
  • a plurality of dots of the pixel 602 are formed by ejection or non-ejection from the orifices #100, #68, #36 and #4 during each of four times scanning 601A, 601B, 601C and 601D of the recording head 601.
  • the density level is maximum, and when not ejected from all orifices, that is minimum.
  • the medium density level between the maximum level and the minimum level is, of course, formed by the combination of absence or presence of ejection from each orifice.
  • Fig. 6 is a block diagram showing a structure of image signal processing composed in the control structure shown in Fig. 4.
  • a simplified signal processor is shown, in which the density level with five levels of one pixel is expressed by ink droplets ejected from four different orifices (also called nozzles hereinafter).
  • input data 101 are 8-bit data representing density levels between 0 and 255 and are assigned in correspondence with each of pixels.
  • the input data of a specified pixel (x,y) are inputted as input data Ixy, to which an error data Sxy are added by an adder 102 in order to obtain data I′xy.
  • the lower 2 bits of data I′xy are stored in a lower 2-bit memory, and the upper 6 bits thereof, as data I ⁇ xy, are transmitted to a comparator 104. That is, a density level value of the data I ⁇ xy is one-fourth of the density level value of the data I′xy to which the error data Sxy are added.
  • a comparator 104 compares in magnitude the data I ⁇ xy with one of threshold data in a threshold memory unit 105. If the data I ⁇ xy is equal to or larger than the threshold data in the threshold memory unit, "1" is, as data Pxy, output and if not, "0" is outputted.
  • the threshold data are transferred to a subtractor 106 to obtain the difference between the threshold value and the data I ⁇ xy.
  • An adder 107 adds the data from this subtractor 106 to the lower 2-bit data of the data I′xy to which the error has already been added. The sum is, as output from the adder 107, transferred to an error distributor 108 to distribute around a noted pixel according to an error diffusion matrix determined by an error distribution coefficient 109.
  • the output Exy is stored according to the error diffusion matrix, in a memory for accumulating the errors distributed around the specified pixel.
  • the output Sxy of a distributed error accumulating memory 110 is added to the data Ixy of the noted pixel to be processed, by the adder 102.
  • a nozzle memory unit 112 has a line memory of 1 bit, and stores the driving data of each orifice, namely "0" or "1".
  • a numeral 113 denotes an output data including the driving data of a line which is now recording.
  • the data (values) of each threshold memory in the threshold memory unit 105 is presets as follows. Threshold memory 1 ⁇ threshold value 8 Threshold memory 2 ⁇ threshold value 24 Threshold memory 3 ⁇ threshold value 40 Threshold memory 4 ⁇ threshold value 56
  • the distribution ratio of the error diffusion coefficient 109 is as that of Fig. 7.
  • the nozzle memory unit 112 is set to zero every one scanning.
  • the above structure is that of the error diffusion of a multi-fixed threshold values. The structure will be described in details hereinafter.
  • the error Sxy which has already distributed by the multi-level (in this case, five-level) halftoning processing of other pixel which has processed before the specified pixel is to be processed.
  • the multi-level halftoning processing of the image signal is essentially performed to the data I ⁇ xy of the upper 6 bits.
  • the data I ⁇ xy are compared with the value of the threshold memory 1, namely the threshold value 8, in the comparator 104. At this time, selected is a threshold memory with the same number as that of the nozzle memory selected by the nozzle selector. Next, as a result of comparison, if the data I ⁇ xy is equal to or larger than the threshold value of the threshold memory 1, then "1" is outputted to the nozzle selector 111 as the output Pxy, if it is smaller than that, than "0" is outputted.
  • the nozzle selector 111 allows the output Pxy to store in the nozzle memory 1.
  • the comparator 104 send the threshold value at the time to the subtractor 106, in which difference between the threshold value and data I ⁇ xy is calculated.
  • the output (difference value) of the subtractor 106 is transferred to the adder 107.
  • the nozzle selector 111 selects the nozzle memory 2 and the threshold memory 2.
  • the comparator 104 compares in a manner similar to that described above, and sends the threshold value to the subtractor 106, in which the processing similar to that described above is performed.
  • the output of the subtractor 106 is added to the last output of the subtractor 106.
  • the nozzle selector 111 selects in order the nozzle memory 3, 4 and the threshold memory 3, 4 and performs the procedure similar to that described above. However, when the value of the output Pxy turns to "0", selecting operation of the nozzle selector 111 would be stopped.
  • the procedure comparing with the threshold value in the multi-level halftoning processing directly corresponds to the procedure for producing the driving data ("0" or "1") and to the assignment of the driving data to each orifice.
  • the number of steps from the image data processing to the driving data producing is decreased, and the load on hardware and/or software is also reduced.
  • Fig. 8 is a flow chart illustrating in details the procedure of the error diffusion processing and the driving data formation, which are described above
  • Fig. 9 is a graph showing the relationship at this time between the input data I′xy, and the number of ejected liquid droplets and the corresponding"orifice number.
  • the specified pixel is formed by the orifices of #4, #36, #68 and #100 shown in Fig. 5.
  • various processing such as the input ⁇ - correction, the color-correction, the black production, the output ⁇ - correction, etc. in the image recording apparatus have already completed, and that the nozzle memories 1 to 4 corresponding to the specified pixel (x,y) each is set to zero.
  • a counter A for counting up the nozzle selector 111 is set to zero, and the accumulated error Exy is also set to zero at step S302.
  • the error data Sxy are added to the specified pixel data Ixy by the adder 102 to yield the dat I′xy.
  • the lower 2 bits of the data I′xy are stored in the lower 2 bit memory 103, and the upper 6 bits thereof are set as the data I ⁇ xy.
  • the value 1 is added to the counter A.
  • the value of I ⁇ xy is compared with the threshold value stored in the threshold memory 1, the numeral of which corresponds to the value of the counter A, i.e. the value 1, by means of the comparator 104. If the value of data I ⁇ xy is equal to or larger than that of the threshold memory 1, then it goes to step S307, and if the value of data I ⁇ xy is smaller than that of the threshold memory 1, then it goes to step S308.
  • "1" is outputted as the output Pxy to the nozzle selector 111, which causes the output value to store in the nozzle memory 1.
  • step S308 when the value of data I ⁇ xy is smaller than the threshold value of the threshold memory designated by the counter A, at he step S308, "0" is outputted as the output Pxy to the nozzle selector 111, which stores in the nozzle memory designated by the counter A, and then it goes to the step S310.
  • the value of the data I ⁇ xy is compared in order with each of four threshold values four times, or these steps, that is, binarizations are repeated until the value of the data I ⁇ xy becomes smaller than the threshold value. Either ejection or non-ejection from the orifices, that is, formation of the driving data of each orifice is determined each time, and the errors are accumulated.
  • step S310 data I ⁇ xy are subtracted from the errors accumulated so far by means of the subtractor, and the result is set as new accumulated errors Exy.
  • step S311 the lower 2 bits of the data I′xy are added to the accumulated errors Exy by means of the adder 107.
  • step S312 the result is distributed to other pixels as process errors in the specified pixel (x,y).
  • the halftoning of the specified pixel (x,y) is represented by each liquid droplet ejected ("1") from three orifices #100, #68 and #36.
  • the error Exy to be distributed when the five-level halftoning processing in the specified pixel is performed, is -6.
  • the above method is not limited within the range of the present embodiment such that a single pixel may be formed by four orifices (recording elements), that is, the number of orifices is not limited to four, and that the above method is effective for such an approach that a single pixel may be formed by lots of orifices.
  • the medium value of the density level corresponding to the number of the ejected liquid droplets was used as a threshold value (the actual threshold value is one-fourth of the density level data). It should be also appreciated that, in the case that the density level does not directly correspond to the number of ejected droplets, the threshold value may be set to adapt to the characteristic of the density level.
  • Fig. 10 is a flow chart illustrating the procedure of embodiment 1A of the present invention.
  • the circuit structure of hardware is similar to that of embodiment 1 shown in Fig. 6.
  • FIG. 10 there is shown the difference between the flow chart of Fig. 10 and that of the embodiment 1 shown in Fig. 8.
  • embodiment 1A there is provided with another counter B besides the counter A.
  • the nozzle memory is selected in accordance with the value of the counter B.
  • the operation of embodiment 1A is the same as that of the embodiment 1 expect this point.
  • the counter B always has one of the count numbers 1 to 4 in succession. That is, the counter is not reset even when the specified pixel is changed, and continues to count. Thus the count number changed from 4 to 1.
  • the assignment of the driving data of each of pixels to the nozzle memory does not always start from the same nozzle memory 1, that is, it starts from the nozzle memory next to one which the driving data "1" was assigned in a one before pixel (see step S507).
  • the orifices to be selected change sequentially every specified pixel. Accordingly, it can be prevented that the same orifice is always used. For example, in the case that the density level of data is 127, it can be prevented that only the combination of the orifices #100 and #68 is used, accordingly, density speckles arising due to variance of an ejection characteristics among orifices.
  • Fig. 11 is a block diagram showing a signal processing structure according to embodiment 1B of the present invention.
  • This embodiment relates to such a method that lots of liquid droplets which forms one pixel are ejected not from a plurality of orifices, but from a single orifice.
  • the same reference numeral as in Fig. 6 identifies corresponding elements.
  • the present embodiment represents a construction for the five-level halftoning processing like embodiment 1.
  • a reference numeral 801 denoted a 3 bit counter, which is reset to zero every pixel.
  • Numeral 802 denotes a 3 bit nozzle memory of which initial value is reset to zero every pixel.
  • the nozzle memory corresponds to one orifice with respect to one pixel.
  • the counter 801 selects the threshold memory 1 in such a state that it is reset to zero. That is, the comparator 104 compares the value of the threshold value memory 1 with the input data I ⁇ xy. The result of comparison is outputted as Pxy like the embodiment 1.
  • the counter 801 adds "1" to the nozzle memory 802, while if it is "0", the counter 801 does nothing. Then, in order to move to the processing of the next pixel, the counter 801 informs the finish of the processing of the lower 2 bit memory, and move to the processing of error diffusion. As described above, the counter 801 counts up to compare in order until the value of Pxy turns to "0". Of course, while this counter is a 3 bit counter, it can be reset to move the processing of the next pixel in the case that the comparison finishes four times before the Pxy turns to zero.
  • the present invention is effective in the case that a single pixel is formed by liquid droplets ejected, not from a plurality of orifices, but from a single orifice.
  • Figs. 12 is a block diagram showing the construction of an image data processing and an assignment processing of driving data according to embodiment 2 of the present invention, which is similar to Fig. 6 in embodiment 1.
  • Fig. 12 the same reference numeral as in Fig. 6 identifies corresponding elements. Therefore, the description of those elements will be abbreviated.
  • Fig. 13A is a schematic illustration of the pixel configuration illustrating a pseudo-halftoning processing of the present embodiment
  • Fig. 13B is a schematic illustration of a weighting mask used in the above processing
  • Fig. 13C is a schematic illustration showing pixels that an error are distributed.
  • FIG. 13A reference numeral 201 denotes the noted pixel (x,y) that the pseudo-halftoning processing is to be performed from now.
  • This specified pixel (x,y) is divided to four pseudo-pixels as shown at a dotted line. These pseudo-pixels are denoted by (x1,y1), (x2,y2), (x3,y3) and (x4,y4), respectively.
  • the input data Ixy of the specified pixel (x,y) have 8-bit data representing density levels between 0 to 255.
  • Numerals 202 to 208 each is a surrounding pixel of the specified pixel 201. In these pixels, the pseudo-halftoning processing have already been finished. In addition, these pixels are also divided into four pseudo-pixels as well. These surrounding pixels each has anyone of values of 0 to 4 as a result of five-level halftoning processing. These values are distributed and maintained in each pseudo-pixel. Thus, the pseudo-pixels of each surrounding pixel have the value of either "0" or "1".
  • a reference numeral 209 in Fig. 13B denotes a specified pseudo-pixel which is one of the pseudo-pixels of the specified pixel.
  • Numerals 210 to 216 denote pseudo-pixels to be weighted with respect to the specified pseudo-pixel 209, to each of which weighting values R1 to R7 (a positive integer) corresponds.
  • Reference numerals 217 and 218 in Fig. 13C denote pixels adjacent to the specified pseudo-pixel 209, to which the error produced in a pseudo-halftoning processing of the specified pseudo-pixel 209 is distributed.
  • the present embodiment 2 relates to how to perform the pseudo-halftoning processing of the five-level halftoning processing, the processing of which would be performed sequentially from one pixel to another pixel, for example, a pixel (x,y), a pixel (x+1,y), a pixel (x+2, y) ⁇ . Referring now to Figs. 13A, 13B and 13C, how to perform the pseudo-halftoning processing of embodiment 2 will be described hereinafter.
  • the pseudo-halftoning processing is performed in a direction from the adjacent pixel (x-1,y) 208 to the right to the pixel (x,y) 201.
  • the two-level halftoning processing is performed to the pseudo-pixel (x1,y1) of the specified pixel (x,y) 201.
  • the threshold value for this two-level processing is determined by the calculation of the weighting mask of Fig. 13B and the surrounding pseudo-pixels of the pseudo-pixel (x1,y1).
  • the error produced by the two-level halftoning processing is diffused on the pseudo-pixels 217 and 218.
  • the pseudo-halftoning processing of this embodiment has the structure such that it is performed only to the pseudo-pixels.
  • the two-level halftoning processing is performed four times to a single pixel, whereby the five-level halftoning processing can be obtained.
  • (n+1)-level pseudo-halftoning processing can be obtained by the structure of carrying out n times a two-level halftoning processing, it is possible to reduce the load on hardware, and to simplify the forming of driving data in the embodiments 1, 1A and 1B.
  • each of the pseudo-pixels in which two-level halftoning processing is performed namely "0" or "1", as described later, is set as driving data to the nozzle memory corresponding to each orifice at the same time the above binarization.
  • the specified pixel (x,y) explained will be how to perform the binarization with respect to four pseudo-pixels (x,y), (x2,y2), (x3,y3), and (x4,y4) of the specified pixel (x,y), and how to perform five-level halftoning processing of the specified pixel (x,y).
  • the data of the specified pseudo-pixel (x1,y1) is equal to I′(x1,y1) that, the errors produced by the two-level halftoning processings in each of the next pseudo-pixel (x1,(y-1)1) to the upper side and the next pseudo-pixel ((x-1)4,y4) to the left side as shown in Fig. 13A, is added to the input data I(x,y) of the specified pixel (x,y).
  • the two-level halftoning processing is performed to this data I′(x1,y1).
  • the threshold value is mean density MV obtained by the following calculation.
  • This ERROR is diffused to the surrounding pseudo-pixel 217 and 218 which are the next pixels to the right side and to the lower side, respectively, as shown in Fig. 13C.
  • the processing of the pseudo-pixel (x2,y2) will be started.
  • the processing of the pseudo-pixel (x2,y2) is similar to that described above, and after the pseudo-pixel (x2,y2) is processed, the value P (x2,y2) is determined to either "0" or "1".
  • the data of the pseudo-pixel (x2,y2) equal to I′(x2,y2) that, the errors which are diffused to the specified pseudo-pixel (x2,y2) by the two-level halftoning processing in each of the pseudo-pixel (x2,(y-1)2) and the pseudo-pixel (x1,y-1), is added to the data I(x,y) of the specified pixel (x,y).
  • the two-level halftoning processing is performed to this I′(x2,y2), in which the threshold value is mean density MV obtained by the following calculation.
  • This ERROR is diffused to the surrounding pseudo-pixel 217 and 218.
  • the processing of the pseudo-pixel (x3,y3) will be started.
  • the above-mentioned process is also applied to the pixel (x3,y3), and then to the pixel (x4,y4), and the value P by two-level halftoning processing of each pseudo-pixel is obtained.
  • the processing of the pixel (x+1,y) is started.
  • the two-level halftoning processing is performed on four pseudo-pixels ((x+1)1, y1), ((x+1)2, y2), ((x+1)3, y3), and ((x+1)4, y4), and then processing of pixel (x+2,y) is started.
  • the result of the pseudo-halftoning processing "0" or "1" is output at every time the processing of each pseudo-pixel finishes performing.
  • the value P of each pseudo-pixel is either "0" or "1"
  • the mean density is calculated in a multiplying and adding circuit 126 on the basis of the values from a weighting coefficient memory 124 and a pseudo-pixel memory 125 which stores the two-level data each corresponding to the pixel which the two-level halftoning processing has been performed.
  • a comparator 104 compares the result of calculation in the multiplying and adding circuit 126 with the data I′(x1,y1) from the adder 102, and output either "0" or "1". At this time, the count of the counter 120 is 3, and it points the memory 1, thus, the result of comparison in the comparator 104 is stored in the nozzle memory 1.
  • the two-level comparison result is also stored in the pseudo-pixel memory 125.
  • an error between the output I′(x1,y1) and 0 or 255, which correspond to the comparison result "0" or “1” respectively, is calculated by a subtractor 106, and its difference is transferred to an error distributor 108, which distributes at a predetermined ratio and causes them to store in a memory section corresponding to the pseudo-pixels (x2,y2) and ((x+1)1, y1) of an error memory 110.
  • the value in the memory may be used when their pixels are performed pseudo-halftoning processing.
  • the counter 120 counts down by 1, thus the counter 120 points a nozzle memory 2 of memory unit 112.
  • the input data I(x,y) of the specified pixel are outputted from input data 101. Accordingly, the processing of the pseudo-pixel (x2,y2) of the specified pixel (x,y) is started, a series of the two-level halftoning processing described above is repeated, and the processing result is stored in the nozzle memory 2.
  • the counter 120 counts down by 1 again.
  • Fig. 14 illustrates, in a direction of scanning of the recording head, a part of pixels formed by the ejection of ink droplets from orifices #100, #68, #36 and #4 respectively, in scannings 801A, 801B, 801C and 801D as shown in Fig. 6.
  • reference numerals 301 to 309 each denotes a pixel, an inside number of each of which represents the number of ejection, that is, the result (value) of the five-level halftoning processing. In other words, that is the sum total of values of the two-level halftoning processing.
  • Squares of the lower portion of each pixel 301-309 represent the pseudo-pixels in which the result "1" of the two-level halftoning processing is obtained.
  • orifice numbers of orifices used in each pixel and scan number of scanning in which the respective orifices eject.
  • the pixel 301 is formed by ejection from the orifice #100 during the scanning 801A, and then the processing of the pixel 302 starts, the two-level halftoning processing is performed to each of it's pseudo-pixels. Also with respect to the pseudo-pixel 302, the result of a first pseudo-pixel is "1" and the others are "0".
  • the pixel 302 is, therefore, formed by ejection from the orifice #100 during the scanning 801A.
  • the two-level halftoning processing is repeated four times in each pixel, and the scanning to form a pixel and the orifice to be used are determined.
  • An example of another pixel will be explained hereinafter.
  • the number of ejection in connection with pixel 304 is 1, and the result of a first pseudo-pixel is "1".
  • the pixel 304 is formed by ejection from the orifice #100 during the scanning 801A.
  • the number of ejection in connection with pixel 305 is 2, and the results of a first pseudo-pixel and a second one are "1".
  • the pixel 305 is formed both by ejection from the orifice #100 during the scanning 801A and by ejection from the orifice #68 during the scanning 801B.
  • the two-level halftoning processing is carried out to each pseudo-pixel and it's result makes the value of the five-level hatftoning processing, whereby it is possible to gain the same effects as the five-level halftoning processing.
  • Fig. 15, 16 and 17 are illustrations illustrating embodiment 2A of the present invention.
  • Fig. 15 is a schematic illustration illustrating a process of forming a single picture with droplets ejected from two orifices. Different from the method as shown in Fig. 15, there are cases where each orifice ejects twice to one pixel during single scanning.
  • a recording head 401 is scanned from left to right of Fig. 15, and ejects ink droplets when there are necessary, forming an image.
  • Reference numeral 401A denotes a position at the beginning of scanning, 401B scanning next to 401A, and 402 a single specified pixel.
  • the number prefixed by a mark # at the recording head represents each of 128 orifices.
  • the density level of a single specified pixel (x,y) 402 is expressed by one or two ejection or by non-ejection from each of orifice numbered #74 and #10 during twice scanning 401A and 401B of the recording head 401.
  • the density level of the specified pixel (x,y) 402 is minimum, when the two orifices each ejects twice, that is maximum.
  • the medium density level between the maximum level and the minimum level is, of course, formed by the combination of the absence or presence of ejection from each orifice.
  • This embodiment also relates to the same five-level pixel forming method as each embodiment described above, in which the numbers 0 to 4 of ejection can be obtained by the sum total of the two-level halftoning processing such as the dither method, the error diffusion method like the above embodiment 2, and stored in the nozzle memories. These values (driving data) is read out every scanning, thus the pixel can be formed.
  • the ejecting timing to the pixel 402 of the orifices #74 and #10 during each of scanning 401A and 401B of the recording head 401 is obtained by pulses of an encoder, etc. indicative of the relationship of the position between the recording head and the medium to be recorded, in which resolution is set such that it may be possible to eject at least twice to a single pixel.
  • nozzle memories 512 and 513 each is a line memory with 2 bits, which correspond to a line of pixels.
  • the nozzle memory 512 corresponds to ejection from the orifice #74, and the nozzle memory 513 to ejection from the orifice #10.
  • the memory is selected by the value of the counter 120 like embodiment 2. For example, if the value of the counter 120 is odd number, the nozzle memory 512 can be selected, and if that is even number, the nozzle memory 513 can be selected.
  • a reference numeral 508 denotes an adder, which adds the value from the comparator 104 to the value already stored in the nozzle memory 512, and stores it again in the nozzle memory 512.
  • a reference numeral 509 also denotes an adder, which adds the value from the comparator 104 to the value already stored in the nozzle memory 513, and stores it again in the nozzle memory 513.
  • the nozzle memory corresponding to a first pixel is reset to zero.
  • the five-level pseudo-halftoning processing method is the same as the method described in embodiment 2, in which the two-level halftoning processing is performed four times.
  • the orifice and the number of scanning corresponding to each pseudo-pixel are as follows.
  • the driving data of the pseudo-pixel (x1,y1) shown in Fig. 13A is used by the orifice #74 during the scanning 410A
  • that of the pseudo-pixel (x2,y2) is used by the orifice #10 during the scanning 410B
  • that of the pseudo-pixel (x3,y3) is used by the orifice #74 during the scanning 410A
  • that of the pseudo-pixel (x4,y4) is formed by the orifice #10 during the scanning 410B.
  • each pseudo-pixel and its corresponding orifices to be used is determined in the above structure.
  • the input data I(x,y) of the specified pixel are transferred from the input 101 to the adder 102.
  • the value of the counter 120 is 3, which points the nozzle memory 512.
  • I′(x1,y1) is obtained by adding I(x,y) to data from the error memory 10 storing errors from the pseudo-pixels in which the two-level halftoning processing has already been performed.
  • mean density is calculated by the multiplying and adding circuit 126 in the same manner as embodiment 2.
  • the comparator 104 compares an output of the multiplying and adding circuit 126 with the output data I′(x1,y1) of the adder 102, and outputs "0" or "1". At this time, the value of the counter 120 equals to 3, and thus points the nozzle memory 512. According, the output of the comparator 104 is stored in the nozzle memory 512 through an adder 508. In the beginning, value "0" is stored in the memories 512 and 513, and, hence the value from the comparator 104 is stored as it is.
  • the output I′(x1,y1) of the adder 102 and a value 0 or 255 are compared by the subtractor 106, and the difference is transferred to the error distributor 108, which distributes the difference or error at a predetermined ratio, and cause them to store in memories of the error memory 110 corresponding to the pseudo-pixel (x2,y2) and the pseudo-pixel ((x+1)1, y1). Values of these memories can be used when object of the pseudo-halftoning processing changes to the concerned pixel.
  • the counter is counted down by 1, of which the value becomes 2, thus points the memory 513.
  • data I(x,y) of the specified pixel (x,y) is outputted from the input 101.
  • the processing of the next specified pseudo-pixel (x2,y2) of the specified pixel (x,y) is started, a series of the above two-level halftoning processing are repeated, and the result is stored in the nozzle memory 513 through an adder 509.
  • the counter 120 is counted down by 1 again, and then points the memory 512.
  • the same processing as that of the pseudo-pixel (x1,y1) is repeated in the specified pseudo-pixel (x3,y3).
  • the value stored in the nozzle memory 512 according to the result of the two-level halftoning processing and the result of this processing of the pseudo-pixel (x3,y3) is added by the adder 508, producing a final value of the nozzle memory 512.
  • the results of the pseudo-pixel (x2,y2) and the pseudo-pixel (x4,y4) are added by the adder 509, producing a final value of the nozzle memory 513.
  • the series of the"above processing is repeated until the counter is counted down to zero.
  • the two-level halftoning processing of each pseudo-pixel is performed four times to the specified pixel (x,y), and any one of values of 0, 1 or 2 is stored to each of the memories 512, 513.
  • FIG. 17 is a schematic illustration similar to Fig. 14 of the embodiment 2.
  • Fig. 17 shows a part of a pixel line in a direction of scanning, in which the pixel line is composed of a plurality of pixels formed by each of orifices #74 and #10 during respective scanning 401A and 401B.
  • a threshold value for two-level processing can be determined by using a weighting mask and values of surrounding pixels of the pseudo-pixel, in which the two-level halftoning processings have already been performed.
  • errors from the surrounding pixels are added to original data of a pixel 601, and this addition is compared with the threshold value.
  • the result of comparison may become "1".
  • the processing of the next pseudo-pixel of the pixel 601 is started, two-level halftoning processing is performed in a similar manner.
  • the result of the second pseudo-pixel becomes "0".
  • the two-level halftoning processing is performed also to the others or two pseudo-pixels, of which the results is stored in the nozzle memories 512 and 513.
  • the pixel 601 is formed bY one ejection from the nozzle #74 during the scanning 401A.
  • the processing of pixel 602 is started, in which two-level halftoning processing is performed to each of pseudo-pixels in a manner similar to that of the pixel 601.
  • the value of the processing of a first pseudo-pixel is "1", that of the others is "0".
  • the pixel 602 is formed by a single ejection from the orifice #74 during the scanning 401A.
  • the two-level halftoning processing is performed to each of the pseudo-pixels, that is, of which processing may be performed four times to each pixel, as a result, the scanning and orifices to be used for forming a pixel are determined.
  • the number of ejection in the pixel 604 is 1 and the value of processing of a first pseudo-pixel is "1", thus the pixel is formed by one ejection from the orifice #74 during the scanning 401A.
  • the number of ejection in the pixel 605 is 2 and the values of processing of the first pseudo-pixel and the second one are "1", thus the pixel is formed by both one ejection from the orifice #74 during the scanning 401A and one ejection from the orifice #10 during the scanning 401B.
  • the number of ejection in the pixel 604 is 3 and the values of processing of the first, the second and the third pseudo-pixels is "1", thus the pixel is formed by both twice ejection from the orifice #74 during the scanning 401A and one ejection from the orifice #10 during the scanning 401B.
  • Fig. 18 is a schematic illustration illustrating embodiment 2B of the preset invention, in which A and B denote how to device the specified pixel (x,y) into pseudo-pixels, and C denotes a pixel dividing method shown in embodiment 2 and 2A described above.
  • a reference numeral 701 denotes a specified pixel (x,y) to be processed
  • 702, 703, 704 and 705 are pseudo-pixels made by dividing the specified pixel into four pixels.
  • two-level halftoning processing is performed in a manner similar to embodiment 2 and 2A.
  • the pseudo-halftoning processing such as the dither method can be performed in the same way with the two-level halftoning processing.
  • the above pixel dividing method with regards to which nozzle memories is assigned to each of the pseudo-pixels, that is, which orifices give ejection composing the pixel, it is possible to simplify in accordance with its hardware.
  • Fig. 19 is a block diagram showing the structure of image data processing according to embodiment 2C of the present invention.
  • a reference numeral 130 denotes a pointer having such the structure that points any one of the nozzle memories 1 to 4. More concretely, the pointer 130 points in order the nozzle memories 1 to 4, and it points the nozzle memory 1 after the nozzle memory 4.
  • the pointer 130 changes in order the memories to point in response to output of the comparator 104. In other words, when the output of the comparator 104 equals to "1", the nozzle memory number of the memory to be pointed is incremented by 1, and when the output equals to "0", that number is not changed. Because, by the structure described hereinbefore, the nozzle memories can be selected in order independent of the pseudo-pixel to be processed, only specific orifices to record an image as shown in Figs. 14 and 17 can be prevented from being used.
  • the nozzle memory pointed by the pointer 130 may be selected by a signal from a random signal generator 1315 as shown in Fig. 20. According to this structure, it is possible to select at random the nozzle memory in the course of processing of the pseudo-pixel. As a similar structure, the nozzle memory pointed at the beginning of processing of the specified pixel can be selected in accordance with a pixel position signal from a pixel position signal generator 1415 as shown in Fig. 21.
  • Figs. 22, 23 and 24 are schematic illustration illustrating assignment of scanning and orifices to each pixel in the structure shown in Figs. 19, 20 and 21, respectively. As seen in these drawings, the orifices to be used can be distributed so that only specific orifices can be prevented from being used.
  • the pointer 130 when making the power of the apparatus, when recording to a new recording sheet, and when scanning of the recording head starts, the pointer 130 may be maintained to reset. That is, it may point the nozzle memory 1, or, only at that time, the nozzle memory may be selected at random by a signal from the random signal generator 1315, or the nozzle memory may be selected in response to an address of the pixel from the pixel position signal generator 1415 shown in Fig. 21. Same effects can be obtained by these selection.
  • the error distribution equals to each pseudo-pixel in the above embodiments.
  • any distribution method can be used so long as the density level of image is maintained as a whole. Accordingly, it is possible to change the error distribution ratio to each pseudo-pixel.
  • the halftoning reproducing method in the embodiments described above is explained by the error diffusion method of the dither method, mean error minimum method, pixel distribution method in meshes, multi-stage division quantization method, MECCA method, CAPIX method, etc. can be applied to the present invention.
  • the pixel was formed with four liquid droplets, however the pixel can be formed also by using any number of orifices more than two.
  • the application of the present invention is not limited to an ink jet recording apparatus, and is applicable to a dot type of printer as a thermal printer.
  • the number of orifices to one picture is 2 n , however, four-level processing by three orifices and six-level processing by five orifices are easily obtained by using many kinds of comparators and threshold values.
  • the present invention achieves distinct effect when applied to a recording head or a recording apparatus which has means for generating thermal energy such as electrothermal transducers or laser light, and which causes changes in ink by the thermal energy so as to eject ink. This is because such a system can achieve a high density and high resolution recording.
  • the on-demand type apparatus has electrothermal transducers, each disposed on a sheet or liquid passage that retains liquid (ink), and operates as follows: first, one or more drive signals are applied to the electrothermal transducers to cause thermal energy corresponding to recording information; second, the thermal energy induces sudden temperature rise that exceeds the nucleate boiling so as to cause the film boiling on heating portions of the recording head; and third, bubbles are grown in the liquid (ink) corresponding to the drive signals. By using the growth and collapse of the bubbles, the ink is expelled from at least one of the ink ejection orifices of the head to form one or more ink drops.
  • the drive signal in the form of a pulse is preferable because the growth and collapse of the bubbles can be achieved instantaneously and suitably by this form of drive signal.
  • a drive signal in the form of a pulse those described in U.S. patent Nos. 4,463,359 and 4,345,262 are preferable.
  • the rate of temperature rise of the heating portions described in U.S. patent No. 4,313,124 be adopted to achieve better recording.
  • U.S. patent Nos. 4,558,333 and 4,459,600 disclose the following structure of a recording head, which is incorporated to the present invention: this structure includes heating portions disposed on bent portions in addition to a combination of the ejection orifices, liquid passages and the electrothermal transducers disclosed in the above patents. Moreover, the present invention can be applied to structures disclosed in Japanese Patent Application Laying-open Nos. 123670/1984 and 138461/1984 in order to achieve similar effects.
  • the former discloses a structure in which a slit common to all the electrothermal transducers is used as ejection orifices of the electrothermal transducers, and the latter discloses a structure in which openings for absorbing pressure waves caused by thermal energy are formed corresponding to the ejection orifices.
  • the present invention can be applied to various serial type recording heads: a recording head fixed to the main assembly of a recording apparatus; a conveniently replaceable chip type recording head which, when loaded on the main assembly of a recording apparatus, is electrically connected to the main assembly, and is supplied with ink therefrom; and a cartridge type recording head integrally including an ink reservoir.
  • a recovery system or a preliminary auxiliary system for a recording head as a constituent of the recording apparatus because they serve to make the effect of the present invention more reliable.
  • the recovery system are a capping means and a cleaning means for the recording head, and a pressure or suction means for the recording head.
  • the preliminary auxiliary system are a preliminary heating means utilizing electrothermal transducers or a combination of other heater elements and the electrothermal transducers, and a means for carrying out preliminary ejection of ink independently of the ejection for recording. These systems are effective for reliable recording.
  • the number and type of recording heads to be mounted on a recording apparatus can be also changed. For example, only one recording head corresponding to a single color ink, or a plurality of recording heads corresponding to a plurality of inks different in color or concentration can be used.
  • the present invention can be effectively applied to an apparatus having at least one of the monochromatic, multi-color and full-color modes.
  • the monochromatic mode performs recording by using only one major color such as black.
  • the multi-color mode carries out recording by using different color inks, and the full-color mode performs recording by color mixing.
  • inks that are liquid when the recording signal is applied can be used: for example, inks can be employed that solidify at a temperature lower than the room temperature and are softened or liquefied in the room temperature. This is because in the ink jet system, the ink is generally temperature adjusted in a range of 30°C - 70°C so that the viscosity of the ink is maintained at such a value that the ink can be ejected reliably.
  • the present invention can be applied to such apparatus where the ink is liquefied just before the ejection by the thermal energy as follows so that the ink is expelled from the orifices in the liquid state, and then begins to solidify on hitting the recording medium, thereby preventing the ink evaporation: the ink is transformed from solid to liquid state by positively utilizing the thermal energy which would otherwise cause the temperature rise; or the ink, which is dry when left in air, is liquefied in response to the thermal energy of the recording signal.
  • the ink may be retained in recesses or through holes formed in a porous sheet as liquid or solid substances so that the ink faces the electrothermal transducers as described in Japanese Patent Application Laying-open Nos. 56847/1979 or 71260/1985.
  • the present invention is most effective when it uses the film boiling phenomenon to expel the ink.
  • the ink jet recording apparatus of the present invention can be employed not only as an image output terminal of an information processing device such as a computer, but also as an output device of a copying machine including a reader, as an output device of a facsimile apparatus having a transmission and receiving function, and as an output device of an optical disc apparatus for recording and/or reproducing information into and/or from an optical disc.
EP92305187A 1991-06-07 1992-06-05 Appareil d'enregistrement et procédé pour la génération de données d'actionnement Expired - Lifetime EP0517545B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP13660891 1991-06-07
JP136608/91 1991-06-07
JP13917592A JP3176123B2 (ja) 1991-06-07 1992-05-29 記録装置および該装置の駆動データ形成方法
JP139175/92 1992-05-29

Publications (3)

Publication Number Publication Date
EP0517545A2 true EP0517545A2 (fr) 1992-12-09
EP0517545A3 EP0517545A3 (en) 1993-03-31
EP0517545B1 EP0517545B1 (fr) 1997-12-29

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP92305187A Expired - Lifetime EP0517545B1 (fr) 1991-06-07 1992-06-05 Appareil d'enregistrement et procédé pour la génération de données d'actionnement

Country Status (5)

Country Link
US (1) US6120121A (fr)
EP (1) EP0517545B1 (fr)
JP (1) JP3176123B2 (fr)
AT (1) ATE161672T1 (fr)
DE (1) DE69223687T2 (fr)

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WO1996032813A1 (fr) * 1995-04-12 1996-10-17 Eastman Kodak Company Systemes de traitement et de copie de photographies
US5909227A (en) * 1995-04-12 1999-06-01 Eastman Kodak Company Photograph processing and copying system using coincident force drop-on-demand ink jet printing

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JP3229454B2 (ja) 1992-10-16 2001-11-19 キヤノン株式会社 インクジェット記録方法およびインクジェット記録装置
JP3164745B2 (ja) 1995-02-13 2001-05-08 キヤノン株式会社 インクジェットプリント装置およびインクジェットプリント方法
JP3190535B2 (ja) * 1995-02-13 2001-07-23 キヤノン株式会社 インクジェットプリント装置およびインクジェットプリント方法
US6805435B2 (en) * 1998-10-16 2004-10-19 Silverbrook Research Pty Ltd Printhead assembly with an ink distribution arrangement
US6704121B1 (en) * 1999-04-16 2004-03-09 Fuji Photo Film Co., Ltd. Image forming method and image forming apparatus
JP2005169736A (ja) * 2003-12-09 2005-06-30 Brother Ind Ltd インクジェット記録装置及びインクジェット記録方法
JP4631506B2 (ja) * 2005-03-30 2011-02-16 セイコーエプソン株式会社 液体噴射装置
EP1732306B1 (fr) * 2005-06-10 2012-11-21 Agfa Graphics N.V. Procédé de traitement d'images pour la réduction d'artefacts

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WO1990009075A2 (fr) * 1989-01-30 1990-08-09 Eastman Kodak Company Formation de demi-teintes numeriques par diffusion d'erreur

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US5909227A (en) * 1995-04-12 1999-06-01 Eastman Kodak Company Photograph processing and copying system using coincident force drop-on-demand ink jet printing

Also Published As

Publication number Publication date
JP3176123B2 (ja) 2001-06-11
JPH05155036A (ja) 1993-06-22
DE69223687D1 (de) 1998-02-05
DE69223687T2 (de) 1998-04-23
ATE161672T1 (de) 1998-01-15
EP0517545A3 (en) 1993-03-31
EP0517545B1 (fr) 1997-12-29
US6120121A (en) 2000-09-19

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